Sessile serrated adenoma: a brief history and current status

Sessile serrated adenoma (SSA) is a polyp of the large intestine, which was first described in 1996. It presents as a solitary lesion or in a setting of a polyposis previously coined as "serrated adenomatous polyposis." The importance of correct recognition of this lesion and distinction from other serrated polyps of the colon is in that the newly described "serrated pathway" of colorectal carcinogenesis seems to apply mostly to SSA and not to other serrated polyps of the colon. This review describes the history of morphologic discovery of SSA and reports on current status of this lesion.